These are great tips! Especially about writing what comes to you, not the story you originally set out to write. Sometimes we’re smarter than we even know and something important is trying to come out! I also recommend checking out StoryShelter – it has lots of question prompts to get you writing about your life. See what questions get your attention and maybe do a free write around them to get the juices flowing!
“Talking about the past can have a healing function, but what we find is that talk, literally, is cheap,” Dr Hunter says. “We speak words and they fly away before we’ve faced what it is they convey.  This is not the case with the written word.  Writers find themselves saying, ‘ I never really thought about it before’ or ‘ I never saw it this way until I started to write it’.
You should check your autobiographical essay for mistakes in spelling, grammar, verb tense, style, punctuation, word forms, etc. No matter how emotional or exciting your writing is, your readers will stop reading as soon as they notice the first grammatical mistake. An illiterate author cannot win the trust of the audience, so you should take this step very seriously.
For example, if you grew up on a farm, you know the difference between the smell of hay and wheat, and certainly that of pig manure and cow manure—because you had to shovel one or all of these at some point. City people probably don’t even know there is a difference. Describing the subtle differences of each and comparing the scents to other scents can help the reader imagine the situation more clearly.

Have you ever read an autobiography? Benjamin Franklin’s autobiography, for example, is an exceptionally powerful one. “DEAR SON: I have ever had pleasure in obtaining any little anecdotes of my ancestors.” That’s how it starts. But, Benjamin Franklin was an exceptional person, after all. That’s the point: autobiographies are for exceptional people. You’re exceptional, too. You have a special story that’s worth sharing. The only thing to learn is how to write a life story about yourself.

I think the first and best step to getting things out – but not necessarily writing your life story for anyone else to read – is to buy a journal. Start writing about your experiences and painful memories. It will hurt, but the only to get past the pain is to go through it. The more it hurts, the better it will be in the long run to process the experience.
These memories are also important because they point backwards to what was, and forwards to what was about to happen, with a sense that there was now a new way of seeing these stretches of time. In each memory, moreover, there is likely to be a huge gift – each will reflect a theme, possibly a major theme, which will play out in the rest of the writers’ life.
Once you have your initial list, elaborate on each key event in your outline. If you're using the autobiograa, fill in the blanks, and then write anything you remember about that point, a little or a lot, whatever springs to mind. Later, you might choose a single event that best illustrates each point in the outline and describe the event, using your theme statement to guide your description.
Why it helps: There’s no need to do the actual examination and investigation now. Instead, just focus on identifying what it is you might delve into someday—in a memoir or in the pages of a journal or just in your mind. What truth is important for you to get at? You have a structure (your three sentences), you have a crucial event (that may have caused or contributed to that life story) and now you have a purpose—a reason for writing that will let you learn, enjoy and even be surprised by the story you’ve been waiting to tell yourself and—maybe, just maybe, the world, as well.
It might be tempting to start your story with "I was born in Dayton, Ohio...," but that is not really where your story begins. It's better to start with an experience. You may wish to start with something like why you were born where you were and how your family's experience led to your birth. If your narrative centers more around a pivotal moment in your life, give the reader a glimpse into that moment. Think about how your favorite movie or novel begins, and look for inspiration from other stories when thinking about how to start your own.

These two sets illustrate how you should show the entire action and then show the entire reaction. Don't mix the two together in one paragraph. Write your entire book in this way — action and reaction, one complete set after another. If one part of the set is missing, readers will sense an awkwardness. If you're writing an autobiography, or anything else, action/reaction sequences will make your writing lively and natural. As you expand your ideas, write in action/reaction pairs.

We told you how to start. When you get through that point, it will be easier to continue. You will follow the plan and you’ll keep developing it. At one moment, you may even notice that the words are pouring themselves out. You’re finally expressing the things you’ve been carrying inside for so long. That may be a torturing process, but it’s also liberating in a strange way.
Why did the author choose to highlight certain events in their life in the memoir? Consider why the memoirist chose a certain section of their childhood or a specific life event as the focus of the book. For example, Didion’s book The Year of Magical Thinking focuses on the recent deaths of her husband and her daughter, while Nabokov’s Speak, Memory focuses on his childhood in Russia. One event is in the recent past while one event is in the very distant past. Yet both events have a very strong, and possibly traumatic, effect on the writers.
Develop a central theme, main idea or thesis that clearly explains the purpose behind your autobiography. For example, your theme might be about how you overcame obstacles to become a stronger person, or it might explain why a particular passion -- such as mountain climbing or rescuing animals -- is so important to you. Back your theme with details and background information about your life experiences. For example, you might explain that your dad is in the military, so you've had to learn how to adapt quickly to new schools and unfamiliar environments. Or, you might discuss what it was like growing up in a poor, single-parent home, but how your family was always willing to take in injured or stray pets.